Orchid names are composed as follows:
Generic name (Genus): to be written in italics with an initial capital letter.
Specific epithet (Species name): to be written in italics without a capital letter.
A cultivar name may be added, specifying a particular clone, to be written in Roman type with an initial capital letter and included within single quotation marks.
Example: Pleione forrestii 'Buttercup'
Pleione = generic name (Genus).
forrestii = specific epithet (species name).
'Buttercup' = cultivar (clone) name.
For hybrid cultivated orchids:
Generic name (Genus) as above.
Followed by grex name in Roman type with initial capital letters.
This may be followed by a cultivar name which identifies a clone, written as above.
Example: Pleione Fujiyama 'Teal'
Where Pleione is the generic name.
Fujiyama = grex name,*
and 'Teal' is the cultivar or clone name.
*grex is the collective noun for the seedlings derived from a hybrid cross, it always has two parental taxa (parents)and may sometimes be written as a formula. For the example given this would be Pleione Fujiyama = P. El Pico x P. Shantung. El Pico and Shantung are grex names referring to the parents of this hybrid grex.
The generic name may also be abbreviated, where the context make its meaning clear, as here to a P. for Pleione. Thus a label might be written Pleione Fujiyama 'Teal' (P. El Pico x P. Shantung), showing the parents of the hybrid. A list of standard abbreviations for orchid genera may be found here
Detailed examples of format and typography may be found in The handbook on Orchid nomenclature and registration, available from the RHS.